Unmanned undersea vehicles are utilized by both the military and commercial enterprises for salvage operations and underwater construction projects. Scanning sonars are indispensable as "eyes" for these undersea vehicles. As the unmanned undersea vehicles get smaller and smaller, the sonar becomes a significant load for the vehicle. There is a need for a small scanning sonar, in the order of the size of a cigar box, that can act as the "eyes" of a small unmanned undersea vehicle so that the load on the vehicle is minimized.
Presently, scanning sonars are built in either one of two ways. One type utilizes curved transducer arrays, and the beams are formed using overlapping sectors on the curved arrays or the beams are formed by mechanical scanning. The disadvantages of the curved array sonar is in the cost and the required beamforming hardware. The cost of the curved arrays is significantly greater than the cost of a linear array. Secondly, each beam requires a unique beamformer since each beam uses different elements of the array. The disadvantage of the mechanically scanned sonar is the mechanical scanner. A mechanical scanner is large and heavy, and is slow in scanning. Accordingly the mechanically scanned sonar has a much lower information rate than that of an electronically scanned sonar.